【摘要】 褪黑素因其具有调节昼夜规律、改善睡眠等功效，被用于功能性乳制品开发。该研究建立了1种基于固相萃取-高效液相色谱-串联质谱(solid phase extraction-high performance liquid chromatography tandem mass spectrometry, SPE-HPLC-MS/MS)技术快速测定牛乳和乳粉中褪黑素的分析方法。样品经蛋白沉淀、超声提取、离心和Oasis HLB柱净化、洗脱，采用电喷雾正离子(positive electrospray ionization, ESI~+)、多反应监测(multiple reaction monitoring, MRM)模式，以水-乙腈为流动相，经C18柱(2.1 mm×100 mm×1.7μm)柱梯度洗脱，外标法定量。结果表明，褪黑素在0.01～10.0 ng/mL线性关系良好，2条标准曲线的相关系数(R)均在0.995以上，样品检出限为0.005 ng/mL、定量限为0.020 ng/mL,在0.2、0.4、2.0 ng/g的3个加标水平上，乳粉和牛乳的日内加标回收率分别为93.1%～101.5%和94.4%～103.7%,日间加标回收率分别为90.5%～102.8%和92.3%～104.6%,相对标准偏差(relative standard deviations, RSDs)为2.5%～6.9%(n=6)。该方法操作简便、高效、灵敏度高，可用于牛乳和乳粉中微量褪黑素的测定，为功能性乳制品开发和监管提供技术支持。更多还原

【Abstract】 Melatonin has been applied in the development of functional dairy products, attributed to its efficacy in regulating the circadian rhythm and improving sleep quality.This study set up a method based on solid phase extraction-high performance liquid chromatography tandem mass spectrometry in rapid determination of melatonin in milk and formula.Samples were processed by protein precipitation, then extracted by ultrasound and centrifugation.The supernatant was purified and eluted by Oasis HLB column.The eluent was conducted in positive electrospray ionization(ESI~+) mode under multiple reaction monitoring(MRM) mode, coupled with gradient elution by water and acetonitrile as mobile phase and C18 chromatographic column(2.1 mm×100 mm×1.7 μm) chromatographic column, quantified by external standard.As a result, the linearity were good in the range of 0.01-10.0 ng/mL, with the regression coefficients(R) in two standard curves were both above 0.995.The limit of detection(LOD) was 0.005 ng/mL and the limit of quantitation(LOQ) was 0.020 ng/mL in real samples.The within-day recoveries of three spiked levels of milk powder and milk were 93.1%-101.5% and 94.4%-103.7%, and between-day recoveries were 90.5%-102.8% and 92.3%-104.6%, and the relative standard deviations were 2.5%-6.9%(n=6).This method is easy, effective and high-sensitive, which can be applied in melatonin determination for milk powder and milk.It can supply important real meaning for the development of functional milk products and technical support of milk market in China.更多还原